ONE-OFF DIY WEAPONS
There are also a number of weapons that appear to be one-offs -- for example, the above air-powered Molotov cocktail launcher. Other examples included a prototype of a grenade launcher, a shotgun based pipe-bomb launcher (seen in action here), a DIY recoilless gun, and a multi-caliber pipe gun.
Some of these weapons are extremely unsafe -- for example, take this shoulder-mounted mortar launcher. Toward the end of the video we see several examples of the weapon being fired, and the last of those examples show the mortar becoming stuck in the end of the barrel, causing the rebel to drop the weapon and run away before the detonation.